Naoki, Vicky, Nutsinee, Matt
We recovered the FDS and got 4.5dB squeezing in IFO with 40 times more CLF power as shown in the attached figure.
First we restored the ZM1/2/3 and FC1/2 OSEM positions to the values in O4a. Then we found the FC green trans in camera and PD. We aligned FC1 and FC2 and successfully locked the FC green. We went to SQZT8 and centered the green camera and green QPD.
Since we aligned the green QPD, the green QPD offset value is not valid anymore so we removed the beam spot control from FC ASC. We made a flag for the beam spot control in sqzparams and it is set to False now. We also set the ADF servo flag to False since the ADF demod phase might not be correct. After we figure out the optimal green QPD offset and ADF demod phase, we should revert them.
We reduced the FC IR gain from -3.5 to -0.1 and reduced the FC ASC gain from 0.1 to 0.005.
We have not done any PSAMS scan so we will do it next week.
I reduced the FC ASC threshold as shown in the attachment. I also reduced the fcWFS_qDip_lock_threshold in sqzparams from 0 to -50000 although I am not sure if this is useful.
The SQZ-CLF_REFL_LF_OUTPUT is 245uW now and was 5.7uW in O4a so the CLF power is 43 times more now.
Since the vent, we haven't recovered our squeeze in the region of that really improves our range: See Yellow BLRMS around 350Hz.
Checked SHG pump launch is ~20.5 - 21mW at both times and OPO green trans rejected is similar.
Trending our other signals, just see that OMC_TRANS_RF3 and CLF_REFL_RF6 and FC_WFS_A_ locking signal sare much larger, I think this is expected from increased CLF power. The NLG is simular 15.8 now, was 17.3. Plots of Jan 10th and March 9th.
